A compression coding technique for video data has widely prevailed and is used for applications such as digital broadcasting, distribution of a video content with an optical disk, and video delivery via a communication network such as the Internet. An H.261 method and an H.263 method standardized by ITU are examples of coding techniques for generating coded data by coding video data with high image quality at a low bit rate and a high compression rate and for decoding coded video data. Further, the coding techniques includes MPEG-1, MPEG-2, and MPEG-4 created by ISO and VC-1 standardized by SMPTE and the coding techniques have been widely used as an international standard.
ITU is an abbreviation of International Telecommunication Union. ISO represents an abbreviation of International Organization for Standardization. MPEG is an abbreviation of Moving Picture Experts Group. SMPTE is an abbreviation of Society of Motion Picture and Television Engineers.
Further, H.264/MPEG-4 AVC (hereinafter, referred to as an “H.264 method”) cooperatively standardized by ITU and ISO is prevailing. NPL 1 discloses an H.264 method. Further, H.265/MPEG-H HEVC (hereinafter, referred to as an “H.265 method”) is standardized in 2013 as a standard relating to compression coding for video data. NPL 2 discloses an H.265 method. An H.265 method is said to be a technique capable of compressing, for each image in video data, a size of the video data approximately by half while ensuring image quality comparable to an H.264 method, and is expected to be used in a wide range of fields in the future.
AVC is an abbreviation of Advanced Video coding. HEVC is an abbreviation of High Efficiency Video coding.
These video coding techniques include, for example, an element technique such as motion compensation prediction processing, orthogonal conversion processing for a predictive error image, quantizing processing for an orthogonal conversion coefficient, and entropy coding processing for an orthogonal conversion coefficient applied with quantizing processing, and therefore are referred to as a hybrid coding technique. These video coding techniques execute an intra-frame prediction processing and an inter-frame prediction based on relevance between pieces of image data relating to a spatial direction and a temporal axis direction, the relevance being one characteristic of image data, and thereby achieve high compression efficiency for video data. The inter-frame prediction includes motion compensation prediction processing of generating a predicted image by correcting a motion of an object such as a subject and a background between pieces of image data temporally close to each other and a position deviation relating to the object.
As an example of the video coding technique, PTL 1 and NPL 5 disclose, for example, coding devices that efficiently execute the video coding processing. These devices reduce a size of a conversion coefficient value series including a quantized orthogonal conversion coefficient, and thereby efficiently execute video coding processing.